This invention relates to a regulated power supply circuit, as well as to a voltage regulator which is employed in such a circuit.
In the past, a number of problems have been associated with regulated power supply circuits which have to cope with wide input voltage ranges. At voltages in excess of 1 kV, only relatively low biasing currents can be fed to the power supply in order to avoid high power dissipation. The standard zener transistor configuration requires excessive zener biasing current which results in a high power dissipation. High voltage transistors exhibit relatively low current gains, and the basic current drawn by such transistors loads any reference and may drastically affect regulation with dynamic output loads.
At present, there exists no single commercially available transistor capable of efficiently providing a low voltage regulated supply from an unregulated input exceeding 1 kV.